1. Field of the Invention
The present invention relates to an optical pickup for use in a disk player such as a DVD player.
2. Description of the Related Art
Conventionally, as techniques of optical pickups, those disclosed in JP-A-11-16205 and the like are known. One such example will be explained with reference to FIG. 13. A photodiode PD is disposed at one end opening 2a of a light passage hole 2 provided penetratingly in a synthetic resin-made base 1 in which a half mirror HM is disposed. A collimator lens QWP and an objective lens OL are disposed in its other end opening 2b, and a laser diode LD and a diffraction grating G are disposed in a laser hole 3 communicating with the light passage hole 2. Laser light is projected from the laser diode LD onto a disk D through the half mirror HM, the collimator lens QWP, and the objective lens OL, and its reflected light is received by the photodiode PD through the half mirror HM to thereby read information recorded on the disk D.
A metallic radiating plate 4 is secured to a laser mounting surface 5 formed at a periphery of the opening of the laser hole 3 in the base 1 by a plurality of (in this arrangement, two) screws 22. An engaging hole 4a provided penetratingly in a substantially central portion of the radiating plate 4 is positioned concentrically with the laser diode LD, thereby causing the radiating plate 4 to abut against a rear surface of the laser diode LD. This arrangement is designed to prevent a decline in the capacity of the laser diode LD when it generates heat due to the projection of the laser light.
In the above-described construction, through holes 4b for insertion of the screws 22 are merely provided penetratingly in the radiating plate 4, as shown in FIGS. 14A and 14B. Consequently, the screws 22 are passed through these through holes 4b and are screwed in threaded holes 23 of the laser mounting surface 5, and heads 22a of the screws 22 are brought into pressure contact with the radiating plate 4. Therefore, the radiating plate 4 is liable to be strained and deformed, so that there are cases where the deformed radiating plate 4 becomes spaced apart from the laser diode LD, thereby making it impossible to sufficiently exhibit a radiating effect (see the phantom lines in FIG. 14B).